Some are transformed into assertions of love. Some become outlets for artistic expression. Others turn into shopping lists. What they are supposed to be, however, are banknotes.

Colombians' passion for adorning, defacing and scribbling on their banknotes is wreaking havoc on the nation's money supply, prompting protests from the central bank which is weary of replacing millions of notes each year.

The bank has launched a television campaign, and awareness courses, to try to wean the population off the habit that keeps the national mint busy.

Examples cited by the bank include sweet if banal expressions of ardour: "Gordis, my love has no price, Memo," was written on a 2,000 peso note, which is worth about 66p.

On the same note someone had adorned the face of General Francisco de Paula Santander, a 19th-century independence leader, with modish spectacles, moles, wrinkles and a goatee.

Jorge Eliécer Gaitán, a politician assassinated in 1948, suffers most from doodling, being the face of the common, lowest denomination, the 1,000 peso note. One of his many indignities is an eye patch, making him resemble a pirate. Even 50,000 peso notes get defaced.

The bank printed 1bn notes annually, of which 70% were to replace deteriorated bills. Of those, one in five were hastened to an early retirement by the nation's doodlers and scribblers.

However, banks and money changers compounded the problem by using stamps and pens to keep track of different denominations. And people went overboard verifying the authenticity of notes with matches and erasers which, ironically, damaged the security seal.

Defacing bank notes – or making money funny, as some would see it – is a crime in many countries. Iran's government responded swiftly after opponents started writing slogans such as "Death to the dictator" on banknotes after last year's allegedly rigged presidential election. Iran's bank declared defaced notes invalid and ordered people to exchange them.